Scanning tunneling microscopy of a liquid crystalline phase of poly((dA-dT).(dA-dT)) induced by a histone H1 peptide.
In this report, we present the first observations of uncoated poly((dA-dT).(dA-dT)) molecules organized in a liquid crystalline phase induced by the binding of a histone H1 peptide. The effect of the peptide on the polymer condensation is clearly illustrated on the large-scale STM images which reveal a well defined spacing between parallel DNA helices. High resolution images of rare isolated molecules of poly((dA-dT).(dA-dT)) exhibit two sets of helical pitch values, 6 and 7.5 nm. While the lower value can be correlated with the pitch of poly((dA-dT).(dA-dT)), the larger one may arise from peptide binding in the polymer minor groove.
Coratger
R
R
CEMES-LOE/CNRS, Toulouse, France.
Chahboun
A
A
Ajustron
F
F
Beauvillain
J
J
Erard
M
M
Amalric
F
F
D003460:Crystallization; D006657:Histones / Q000648:ultrastructure*; D008854:Microscopy, Electron; D016252:Microscopy, Scanning Tunneling; D011067:Poly dA-dT / Q000737:chemistry*
D006657:Histones; D011067:Poly dA-dT